Changing from a double to a compact (and back again)

[zizou]

Currently have a double (53/39) on my bike and find it good for my normal riding but im planning to do some riding in the alps next summer and think converting to a compact for that would probably be a good idea. No doubt a stupid question but what would i need to do? I know i cant just fit smaller chainrings and will need a new chainset but will the front and rear deraillers still be ok? And probably an even dafter question will i need a new left crank arm (would that come with the new chainset?) or will the old one do?

Also would it be easy to change between a double and a compact depending on the terrain i'd be riding? Or is it something you do then stick with until want to change permantly?

Thanks for any info

 

[Vapin' Joe]

The new chainset will come with a pair of cranks. Your existing front and rear mechs will be ok, though the front will need to come down the tube and you will probably need to take a link out of your chain.

Depending on what cassette you run now it would be cheaper to get one with a bigger bottom sprocket rather than faff about with chainsets (for example if you have a 25t replacing the cassette for one with a 27t would be the same as dropping about six teeth on the inner ring).

 

[Lighthorse]

A special set up for keeping a good tempo up long and/or steep hills. Highest gear is 76", which is higher than most road going fixed bikes. Lowest is 23", 22 Chainring and 25 sprocket. It is an MTB chainset with the outer 44 chainring removed and some trimmed washers in its place to get the bolts tight. The front mech is as low as possible but works well. The 32 chainring has a chainline the same as the large ring on a road triple.

 

[zizou]

i think i already have a 27t cassette so unfortunately the cheap option doesnt look possible.

Thanks for the info though hopefully wont sound like a total idiot when i go into the bike shop now